post
https://api.intersoftsapient.net/v4/shipments/preallocateTrackingNumber/rm
Receive a Royal Mail Tracking Number that will be pre-allocated to the service and destination supplied in the request. No shipment or label will be produced using this endpoint.
This service can be used in conjunction with the Create Shipment endpoint by specifying the TrackingNumber in the CarrierSpecifics or OfflineBarcodes section with the pre-allocated TrackingNumber returned in this service response.
Note: This endpoint can only be used for services that are assigned a tracking number.
401Unauthorized
403Forbidden
500Internal Server Error
